This invention relates to a method and apparatus for repairing the wall of a manhole. More particularly, but not exclusively, it relates to a method and device for treating the wall of a manhole using a bladder and material capable of curing and hardening, such as a grout or thermoset resin. The bladder expands to conform to the wall of the manhole and the material capable of curing and hardening is disposed between the wall and the bladder or on the interior surface of the bladder.
Conventional manholes include a lower or bottom panel, a barrel having a relatively constant diameter adjacent the panel, a concentric or eccentric cone extending upwardly from the barrel, one or more adjusting rings to adjust the overall height of the manhole, and a casting frame on top of the adjusting rings to support an elevation substantially level with the surrounding pavement. The casting frame is preferably sealed to the uppermost adjusting ring to preclude or minimize water flow into the manhole. The cone and adjusting rings are commonly known as the manhole chimney. Most manhole structures are unique in size and shape with varying diameters and depths. Also, bricks often form a portion of the wall of the manhole.
Substandard construction methods can lead to damage or deterioration of the manhole structure. Thus the manhole is vulnerable, allowing water and subsidence of soil to enter the manhole, which eventually leads to a structural failure of the manhole.
One presently known method of repairing manholes is the placement of a coating of a cementitious grout onto the interior surface of the manhole wall. The grout is applied in an uncured state and is permitted to cure. Methods of applying the grout include troweling the grout onto the wall of the manhole after spraying or slinging the grout onto the wall of the manhole. The manhole wall must be clean and free from water leaking through the manhole walls. Here, it is necessary for a person to enter into the manhole to plug water leaking into the manhole. A final troweling step is usually required by a person entering the manhole in order to obtain the desired compaction, surface and thickness for the curable and/or hardenable material.
Additionally, resin, such as an epoxy, a polyurethane, polyuria or other thermoset resins have been applied to manhole walls by spraying or slinging the polymer onto the manhole wall. The polymer requires the manhole wall to be clean and free from water leaking with a prepared surface adequate for adhering the polymer to the manhole wall.
Resin-coated sleeves have also been used for repairing a manhole chimney. However, to accommodate changes in diameter of the manhole, the use of an impermeable coating on the sleeve is problematic, as a substantial coating can prohibit the necessary stretching of the sleeve, because when the sleeve stretches, the coating becomes prone to delamination from the sleeve. Furthermore, applying a coating to a fabric sleeve and sealing the seam of a fabric sleeve increases the cost for producing the sleeve. As such, problems remain in the art and a need exists for an improved method and means for repairing the wall of a manhole.